New brain implants enable paralyzed monkeys to control their legs

Wednesday, November 16, 2016 by: David Gutierrez, staff writer
Tags: paralysis, spinal implants, motor control

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(NaturalNews) Researchers have successfully tested a brain-spinal implant to allow the brains of paraplegic monkeys to once again control their legs. The study was conducted by researchers from the Ecole polytechnique federale de Lausanne (EPFL) in Switzerland.

In recent years, researchers have made great strides in restoring the brain's control in cases of paralysis. But the new study is the first to transmit a signal from the brain to the spinal cord, and also the first to function using wireless technology.

Paraplegia is most often caused by an injury to the spine that disrupts the ability of nerve signals to travel between the brain and the motor muscles of the legs. When a spinal injury occurs higher on the spine, it can instead result in quadriplegia.

The new method uses a wireless signal to transmit a signal from the brain across the severed spine to a receiver on the other side.

"The brain is in control," lead researcher Gregoire Courtine said.

"This study shows we can take brain signals and leverage them and link them to leg movements, which has not been shown before."

Wireless signal leaps across severed spine

The researchers created small lesions in the spinal cords of rhesus macaques – large enough to induce paraplegia, but small enough to heal on their own within a few weeks. Once they had confirmed paralysis, the researchers implanted two devices.

The first, as big as a dime, was implanted in the region of the monkeys' brains that control large muscle movement (the motor cortex). This device interprets the signals emitted by the brain when the monkeys themselves decide to move, then converts it into a wireless signal that is transmitted to the second receiver, located just past the spinal lesion.

"We extract the general intention of movement," Courtine said.

The second implant converts the signal back into its initial form and releases electric impulses that stimulate the nerves to produce the movement ordered by the brain. The procedure was so successful that the cyborg animals were able to walk normally almost immediately after the surgery, without needing any training or physical therapy.

In a prior study, the same researchers used a similar device to enable paralyzed rats to walk and even climb stairs.

Previous research has focused on ways to trigger paralyzed limbs externally, either through external implants or through prosthetic devices. The new study is the first to restore movement by directly activating the spinal cord.

Recently, Dr. Ali Rezai and colleagues from Ohio State University made news when they enabled a 24-year old man, Ian Burkhart, to control a right hand and fingers that had been paralyzed for six years. Those researchers used brain implants to activate a sleeve worn on the outside of Burkhart's arm, that in turn contracted his muscles physically.

'Step by step'

The researchers and outside observers all warned that the new wireless device has a long way to go before it can be used on humans.

"Getting movement in the lower extremities is a much bigger challenge in humans," said Rezai, who was not involved in the study. That's because the human motor cortex is much deeper in the brain than that of monkeys. Additionally, human legs are substantially more neurologically complicated than monkey legs. But Rezai expressed optimism about the EPFL team's ability to overcome these hurdles.

The EPFL researchers are now conducting a feasibility study to test their spinal implants on two human volunteers, with six more to receive the devices over the next two years. If the results are promising, they will move on to larger studies.

"We're planning to bring this into clinical application step by step," Courtine said.

Sources for this article include:

Edition.CNN.com

Telegraph.co.uk